The invention relates to an energy guiding chain for guiding hoses, cables or the like that has numerous chain links, where adjacent chain links are connected to one another in articulated fashion, where the chain links have opposing straps with inside and outside lateral surfaces as well as narrow surfaces perpendicular thereto and essentially parallel to the longitudinal direction of the chain, at least some of the chain links have at least one cross-member connecting the straps, the articulated joint between adjacent chain links is located between the narrow surfaces of the straps, and the energy guiding chain can travel, forming a lower strand, a deflection zone and an upper strand.
Various generic energy guiding chains are known, in which adjacent straps have lateral overlapping areas provided with joint pins and corresponding recesses in order to assemble the articulated joint. The articulated joint is located half-way up the straps. An energy guiding chain of this kind is known, for example, from EP 0 803 032 B1. Although energy guiding chains of this kind have proven to be very effective in principle, they have the disadvantage that the articulated joints made of joint pins and corresponding recesses are subject to wear due to frictional forces. This wear leads to a certain need for repair and servicing of the energy guiding chain and, furthermore, is undesirable in certain fields of application, such as food production or the production of devices under clean-room conditions, such as semiconductor products.
Cable guiding devices are further known from EP 0 789 167 A1, for example, where the chain links are connected to one another in articulated fashion by a long, flexible strip, so that the cable guiding device can travel in virtually abrasion-free fashion. Because the long strip is mounted on the cross-members connecting the straps of a chain link, the articulated joints of the chain links are located at the lower end of the straps. Consequently, the neutral fibre of the cable guiding devicexe2x80x94which does not change in length when the energy guiding chain bends, in contrast to the areas spaced apart at the height of the articulated jointsxe2x80x94is also located at the lower end of the chain straps. However, this is a disadvantage in various applications.
Consequently, an object of the invention is to provide an energy guiding chain that has articulated joints located between the narrow surfaces of the chain straps, allows low-wear, abrasion-free travel, and is simple and inexpensive to manufacture.
According to the invention, the object is solved by an energy guiding chain, in which the articulated joints include joint elements that are elastically deformable in the bending direction of the chain links and designed as separate components, where the joint elements extend at least partially between the inside and outside lateral surfaces of the straps. During pivoting motion, the elastically deformable joint element exerts elastic restoring forces on the two adjacent chain links, preferably through the entire pivoting angle. When the energy guiding chain is in an extended position, the joint element preferably extends straight in the longitudinal direction.
Due to the design of the energy guiding chain according to the invention, it is possible for the chain to travel without abrasion, where the position of the joint element on the straps, its dimensions and, in particular, the material it is made of can be optimally adapted to respective requirements, regardless of the design of the straps. For example, the straps and the joint elements can be made of different materials, particularly different plastic materials. The joint elements can be made of a material with high long-term flexural strength, notch resistance and/or suitable elasticity. The elastic properties of the joint element are preferably selected such that the joint element remains in the elastic range under every expected bending load and exerts elastic restoring forces on the straps connected by it in the event of deformation. The material of the straps can ensure particularly high dimensional stability (against tension, torsion and/or compression forces) and high flexural strength of the straps, and also of the chain links in general. In particular, the material can display low sliding friction, which is advantageous in energy guiding chains in which the upper strand slides on the lower strand when the energy guiding chain travels.
Because the straps and joint elements are designed as separate parts according to the invention, the straps can be designed to absorb virtually all compression and tension forces acting on the energy guiding chain in the longitudinal direction, while the function of the joint elements is exclusively limited to the formation of articulated joints subject to no significant load caused by compression or tension forces.
The joint element preferably extends entirely between the inside and outside lateral surfaces of the straps. The width of the joint elements can be exactly equal to the width of the straps at the height of the joint elements, thus avoiding areas of the joint elements projecting beyond the sides of the straps.
The chain links can each have an upper and lower cross-member, which close off the space between opposing straps from the outside, where one of the cross-members can also be designed as a split cross-member. In the design according to the invention, it is also possible when using engaging stops, for example, to provided only every second or third (etc.) chain link with cross-members. The cross-member connecting opposing straps can be integrally molded on the straps or mounted in detachable fashion, particularly by means of a suitable snap connection or other mounting elements. At least one of the cross-members is preferably of rigid design and mounted rigidly on the opposing straps.
When the energy guiding chain is in a straight position for assembly, the joint element is preferably located at a vertical distance between the upper and lower cross-members, if present, or between the mounting elements for cross-members, and at a vertical distance from the cross-members, particularly at a point near the middle of the strap height that is at least one-quarter of the strap height away from the lower edge of the straps. In particular, the joint element can be positioned half-way up the straps. In this way, the chain links can be arranged symmetrically relative to the neutral fiber of the energy guiding chain, where the neutral fiber does not undergo any change in length when the chain moves from a straight to a curved position. This is advantageous for various applications, because the lines guided inside are subjected to a more uniform load during bending motion of the energy guiding chain.
The chain links preferably have means for damping the noise caused by operation of the stops. The noise damping means are preferably designed as brakes arranged in the region of the stops and/or the corresponding stop surfaces. In particular, the noise damping means can be arranged in the pockets of the corresponding straps that accommodate the stops. The stop surfaces, which simultaneously delimit the pockets on the front sides of the straps and can therefore be of web-like design, can be of elastic design, for example by selecting a suitable material or material thickness, where the material of the stop surfaces can have a higher modulus of elasticity than the material of the adjacent strap areas. Alternatively and/or additionally, the stops themselves can be of elastic design, for example at least partially made of a material of elevated elasticity. Separate damping elements, such as damping strips made of a noise-damping material, can also be provided on the stops and/or corresponding stop surfaces, preferably inside the pockets accommodating the stops. The stops and the corresponding stop surfaces can additionally or alternatively be designed such that a first partial area of a stop comes into contact with a first partial area of the corresponding stop surface at a first point in time, and a second partial area of the stop comes into contact with a second partial area of the stop surface at a later point in time, so that at the end of the contacting process, the entire active surface of the stop is in contact with the corresponding stop surface.
The joint elements are particularly preferably designed as spring elements that exert elastic restoring forces on the adjacent chain links when the chain links are bent out of the straight position of the energy guiding chain. This has a noise damping effect when the energy guiding chain is in motion. The elastic restoring forces preferably cause return motion of the chain links through their entire pivoting angle. The restoring forces can be so high that return motion of the chain links occurs automatically all the way into the limit position of the chain links when the energy guiding chain is straight. This can apply to an empty energy guiding chain, as well as to one containing at least one guided element, such as a hose, a line or the like, or to a maximally loaded energy guiding chain.
The joint elements can be of various designs. They can have a changing cross-section and/or areas of different material thickness between the mounting areas. The cross-section and/or material thickness preferably increase away from the mounting areas and can reach a maximum in the central region of the joint element. The cross-section and/or material thickness can also be constant in a first section starting at the respective mounting area, and then vary starting at a distance from the mounting area, particularly in that the cross-section and/or material thickness increase or have an area of less material, such as a constriction or inside cavity. The change in cross-section and/or material thickness preferably occurs in the primary plane of the associated chain straps. A change in cross-section can particularly be achieved by a vertical and/or lateral offset of an area of the joint element. An area of less material can be provided with a constant or changing cross-section in the respective area of the joint element, where the cross-section can increase or decrease. For example, an inside cavity can be provided in conjunction with a constant or changing cross-section of the joint element. A closed or open cavity, particularly one that is open on the side in assembly position, can also be provided, which can correspond to a split in the material that forms different strands with a constant overall material thickness. The individual strands can be of different shape, such as straight or curved, and display indentations and/or protrusions, where any combinations are possible. The change in cross-section and/or material thickness can be continuous or incremental. The travelling characteristics of the energy guiding chain can be defined by different designs of the joint elements, e.g. the force required to bend the straps, the change in this force as the pivoting angle changes, or the noise damping characteristics of the joint elements, which can be based on the exertion of restoring forces during bending. This is of particular importance in the case of exchangeable joint elements.
If the joint element is designed as a spring element, each chain link can be provided with contact surfaces that lie against the joint element through the entire pivoting angle, thereby absorbing the elastic restoring forces acting on the chain links during elastic deformation of the joint element due to the bending of the chain links. The joint element is preferably arranged between the contact surfaces in a press fit. The contact surfaces of the straps, and the corresponding surfaces of the joint element, preferably have plane surfaces, whose surface normals are parallel to the inside and outside lateral surfaces of the straps and perpendicular to the longitudinal direction of the energy guiding chain when it is in straight position.
The joint element can be designed as a plate-like component, meaning also a strip-shaped component. In this case, the joint element has essentially flat top and bottom sides, which face the top and bottom sides of the straps. Areas of the straps preferably contact the top and/or bottom side of the flat areas of the joint elements. However, the joint elements can also have other suitable cross-sections.
On the other hand, the joint element can also be designed as a component that is curved in the plane parallel to the inside and outside lateral surfaces of the straps, so that it generates preliminary tension in a bending direction when inserted in the straps in the straight, longitudinal position.
Mounting areas of the joint element can contact the two adjacent side straps, which absorb tension forces acting in the longitudinal direction of the energy guiding chain. To this end, the joint element can be mounted on the adjacent straps by means of a force, form and/or bonded fit. The tension-absorbing mounting of the joint elements on the straps can be such that it is only geared to low tension forces, e.g. to facilitate assembly of the energy guiding chain. To this end, the mounting areas of the joint elements can display top or bottom-side projections, preferably on the free ends facing away from the elastically deformable areas, which can extend over the entire width of the joint elements. Additional tension-absorbing means can be provided if necessary to absorb higher tension forces.
The respective joint element can be designed for the articulated connection of exactly two adjacent chain links in the longitudinal direction of the energy guiding chain. The joint element can also connect several chain links to one another in articulated fashion and, for this purpose, extend over the length of a number of chain links, such as three to ten or more chain links. As a result, several consecutive joint elements can be provided in the longitudinal direction of the energy guiding chain, each of which connects chain links to one another in articulated fashion in only one section of the energy guiding chain. Consequently, if a joint element needs to be replaced, only one section of the energy guiding chain needs to be disassembled, instead of the entire chain. If appropriate, the joint elements can also extend over the entire length of the energy guiding chain. If each joint element connects more than two chain links, connecting areas having a width smaller than that of the straps and/or the elastically deformable areas of the joint elements, can be provided between the mounting areas of the joint elements by which the joint elements are connected to the two adjacent chain links. As a result, the joint elements extending over several straps can be handled as a single piece. The connecting areas can be arranged in the cross-sectional area of the straps and be flush with the outside of the chain links. In this context, the areas of the straps located above and below the joint elements can be connected by a web, so that the straps are designed as a single piece.
The joint elements are preferably located in recesses in the chain straps. The recesses are preferably open on the end facing the adjacent strap that is connected by the respective joint element. Additionally or alternatively, and regardless of the length of the joint elements, the recesses in the chain straps that accommodate the joint elements can be open on the lateral surfaces facing towards or away from the inside of the energy guiding chain, so that the joint elements can be inserted into the recesses and mounted in the straps in a direction that is transverse, preferably perpendicular, to the primary plane or the lateral surfaces of the straps.
By means of a force, form and/or bonded connection to the straps, the joint element can be prevented from disconnection from the straps perpendicular to the primary plane of the straps and/or from rotating transverse to the straps, particularly if the joint element is arranged in a laterally open recess in the straps.
It is preferable for at least one of two adjacent straps, preferably both, to have recesses on the face end associated with the adjacent strap at the height of the joint element, which are open at the face end and through which the joint element extends. Based at least on the straight position of the energy guiding chain, the recess extends on the side of the joint elements facing the bending direction of the links, preferably on both sides of the joint elements. This play enables the joint element to bend in the manner of a leaf spring, where the central region of the elastically deformable area of the joint element has a slight vertical offset relative to the two adjacent straps during pivoting motion. This results in smoother, less noisy rolling motion of the energy guiding chain.
At the height of the pivoting axis of adjacent straps relative to one another, preferably at the height of the straps and/or in the longitudinal direction of the energy guiding chain, the recess preferably extends from the join element over more than half, or more than twice the thickness of the joint element, e.g. over roughly three to five times the thickness of the joint element or more. The recess formed by the two, facing recesses of adjacent straps can be circular, elliptical or some other shape. The longitudinal extension of the recess can be 20 to 60%, preferably 35 to 45%, e.g. approx. 40% of the length of the joint element or of the distance of the form-fit connecting means securing the joint element to the straps. The recess advantageously extends from the joint element over only part of the strap height and ends at a distance from the top or bottom edge of the strap.
Adjacent straps preferably have interacting means that absorb compression and/or tension forces acting on the energy guiding chain. This relieves the compression and/or tension forces acting on the connecting areas between the joint elements and the straps. The means that absorb the compression and/or tension forces are preferably designed as corresponding projections and undercuts in the form of recesses in the adjacent straps. The projections are preferably arranged on the inner or outer sides of the straps and extend laterally from these towards the inside of the energy guiding chain or in the opposite direction. The recesses for accommodating the projections are limited in the longitudinal direction of the chain by an abutment for the projections that absorbs compression and/or tension forces, so that tension and/or compression forces can be absorbed in the longitudinal direction of the chain. The recess can be closed around part or all of its circumference. The corresponding areas of adjacent straps that absorb tension and/or compression forces can also be designed as corresponding stops that limit the pivoting angle of adjacent chain links relative to one another.
The straps advantageously have overlapping areas that extend in the direction of the adjacent straps and also reach around the sides of the straps. The overlapping areas are preferably provided on each strap, above and below the joint elements. In this context, the overlapping areas can extend from a central region of the straps relative to the longitudinal direction of the chain, whose wall thickness is greater than the wall thickness of the overlapping areas. The overlapping areas considerably increase the lateral stability of the energy guiding chain.
The overlapping areas of a given strap, which are associated with an adjacent strap and located above and below the joint element, are preferably separated from one another by a cut-out opposite the central region of the strap, where the cut-out extends over the entire width of the strap. The cut-out is preferably also at the height of the respective joint element and can have the form of a segment of a circle in reference to a circle that is drawn through the center point of the joint element and lies in the primary plane of the strap. As a result, the length of the strap, and thus also its weight, can be reduced substantially. Preferably, the overlapping areas essentially extend only over the pivoting angle of the straps plus the wall thickness of projections or their corresponding contact areas, which limit the pivoting angle or act as means that absorb tension and/or compression forces. These areas are preferably of web-like design and extend perpendicular to the pivot direction of the straps.
In addition, the overlapping areas, which face an adjacent strap and are located above and below the joint element, are preferably located on different sides of the straps, i.e. on the outside and inside lateral surfaces, or on different sides of the central primary plane of the straps. This also includes arrangements in which the overlapping areas are at a lateral distance from the outermost or innermost areas of the straps, e.g. any thicker areas. The overlapping areas thus display a lateral offset relative to one another. In this context, the corresponding overlapping areas of adjacent straps preferably lie laterally opposite to only one overlapping area of the respectively adjacent strap. This substantially increases the lateral stability of the energy guiding chain. In particular, at least one or both of the overlapping areas defined above can be provided with projections on the side facing the corresponding overlapping area of the adjacent strap, which can be designed as stops or means to relieve or absorb tension or compression forces, for example, without be restricted to this, so that, for assembly purposes, adjacent straps can be tilted or twisted about their longitudinal axes and brought into contact with one another at the face ends, and subsequently rotated about their longitudinal axes, in order to bring the overlapping areas, which are opposite one another in reference to the central primary plane, into lateral contact with one another, whereby the projections engage. This arrangement provides the energy guiding chain with particularly high torsional stability.
The overlapping areas facing an adjacent strap can, however, also be located on the same side of the central strap plane, as in conventional chains with links.
The overlapping areas, which are each arranged on the outside or inside of the strap, can be positioned diametrically opposite each other, so that one of the overlapping areas is located above, and another below the articulated joint.
The arrangement and geometry of the overlapping areas can be varied in many ways. In a particularly advantageous design, the straps are provided with at least two overlapping areas, which have free face ends that face the respectively adjacent strap and are at different angles W1, W2 to a direction R, which is perpendicular to the longitudinal direction of the chain and lies in the primary strap plane. In this context, the face ends are preferably essentially perpendicular to the pivot direction of adjacent chain links. The overlapping areas with face ends at different angles are preferably associated with only one adjacent strap. Each strap can have four overlapping areas, each of which faces an adjacent strap, where the face ends of three or less of the overlapping areas are perpendicular, or essentially perpendicular, to the longitudinal direction of the chain and the face end of at least one or more of the overlapping areas is at an angle to the longitudinal direction of the chain. The angle of the face end to the direction perpendicular to the longitudinal direction of the chain can be approximately 15 to 60xc2x0, preferably about 30xc2x0. In particular, two different types of overlapping areas can be provided on one strap, each of which is at a different angle from the perpendicular defined above. All overlapping areas can extend over the same pivoting angle, which essentially corresponds to the maximum pivoting angle of adjacent chain links relative to one another.
Adjacent straps are preferably provided with at least one projection, which is covered by an area of the adjacent strap with only little or no play, this preventing the vertical displacement of the straps relative to one another. The degree of play is preferably designed such that the areas are guided on one another during pivot motion of the chain links without making contact, in order to prevent abrasion. When a force is exerted on the straps that causes the vertical displacement of the straps relative to one another, the covered areas of adjacent straps engage, thereby limiting the vertical displacement. The areas of adjacent straps preferably cover one another over the entire pivoting angle, so that the vertical displacement of straps relative to one another is prevented over the entire pivoting angle. The degree of play can be reduced to zero in at least one or both limit positions of the chain links. The projections that prevent vertical displacement can simultaneously function as stops. They can be provided on the overlapping areas or on the central area of the straps and project from the side of the straps towards the inside or outside, or extend in the primary plane of the straps. The projections can be provided in the region of the top edge of the straps, adjacent to the joint elements, or in some other suitable place.
Furthermore, adjacent straps are preferably provided with interacting stops that limit the pivoting angle of the straps in both limit positions. The stops can be designed as projections extending in the primary plane of the straps and projecting in the longitudinal direction of the energy guiding chain from the central strap area, on which overlapping areas can be integrally molded. The stops can also follow on laterally from the overlapping areas. Of course, other suitable stops can also be provided.
The stops are preferably located immediately adjacent to the joint elements, so that the stops come into contact with each other at only a low angular velocity, this enabling the energy guiding chain to travel with low noise generation. The stops are preferably provided directly around the outside of recesses that surround the respective joint element with play, in order to facilitate bending of the joint element. The stops are preferably provided on the side of the central areas of the straps facing the inside of the energy guiding chain and can display a common lateral surface with the adjacent overlapping area. Thus, the wall thickness of the stop roughly corresponds to half the wall thickness of same central area.
The straps of a chain link can be designed in the manner of cranked straps, which can be mirror-symmetrical. The energy guiding chain can also be constructed of opposing strap strands consisting of alternating inside and outside straps, or in some other suitable way, e.g. with forked straps.